For a patient with pernicious anemia, which vitamin is you expected to administer?

Pernicious anemia is primarily characterized by the body's inability to absorb vitamin B12, usually due to a lack of intrinsic factor, a protein essential for the absorption of this vitamin in the intestines. As a result, individuals with pernicious anemia require vitamin B12 supplementation to overcome this deficiency.

Administering vitamin B12 helps to restore adequate levels of this essential nutrient, which plays a critical role in the production of red blood cells, DNA synthesis, and neurological function. Without sufficient vitamin B12, patients can experience symptoms such as fatigue, weakness, and neurological issues.

In this context, vitamin B12 is the correct choice due to its specific involvement in managing pernicious anemia. The other vitamins listed do not play a direct role in the treatment of this condition. Vitamin C, for example, is important for the immune system and skin integrity but does not address the underlying deficiency in pernicious anemia. Similarly, vitamin A and vitamin D have their respective roles in vision and calcium metabolism but do not have a therapeutic impact on vitamin B12 absorption or deficiency.